Halogen-containing aromatic compound

ABSTRACT

The present invention relates to halogen-containing aromatic compounds and methods thereof. The present invention relates a halogen-containing aromatic acid dianhydride, halogen-containing aromatic tetranitrile compound, halogen-containing m-phenylenediamine compound and fluorine compound, and a method thereof.

Under 35 USC § 120, this application is a continuation application ofU.S. application Ser. No. 10/133,158 filed on Apr. 26, 2002, now U.S.Pat. No. 6,916,959, which in turn claims foreign priority under 35U.S.C. 119 to applications filed in Japan, serial number 2002-142028,filed May 11, 2001, Japan serial number 2001-142029, filed May 11, 2001,Japan serial number 2001-142031, filed May 11, 2001, and Japan serialnumber 2001-142032, filed May 11, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to halogen-containing aromatic compoundsand methods therefor. More specifically, the present invention relatesto a halogen-containing aromatic acid dianhydride (HAA), ahalogen-containing aromatic tetranitrile compound (HTC), ahalogen-containing aromatic tetracarboxylic acid, a halogenatedm-phenylenediamine compound (HPC), and a fluorine compound, and methodstherfor.

2. Description of Related Art

(HAA; HTC)

Heretofore, halogen-, in particular fluorine-containing aromaticcompounds are known to be useful as raw materials for resins which aresuperior in heat resistance, chemical resistance, water repellentproperty and low dielectric property. These resin materials arelightweights compared to conventional inorganic materials. Thesematerials have characters that these excel in shock resistance andworkability, and are readily handled. For these reasons, these materialshave been used for wiring base plate, photosensitive and liquid crystalmaterials.

The conventional halogen-containing aromatic compounds are produced byreplacing a straight chain hydrocarbon group, such as perfluoroalkyl andperfluoroalkenyl groups, with an aromatic ring. However, there is adrawback that heat resistance become lowered by the introduction of sucha group.

For introducing a halogen therein without lowering heat resistance, itis considered that halogens are directly replaced with groups ofaromatic rings. Direct replacement of halogens with groups of aromaticrings is not well known.

(HPC; Fluorine Compound)

Tetrafluoro m-phenylenediamine and halogenated m-phenylenediaminecompounds are important intermediates for synthesizing dye, medicine,agricultural chemical and macromolecule compounds, and useful for rawmaterials of resins excellent in heat resistance, water repellentproperty, chemical resistance, and low dielectric property. Furthermore,these are suitably used for charge-transfer agents (in particularpositive hole-transfer agents) in the fields of solar battery,electroluminescent elements, and electrophotography photosensitive body.

For this purpose, m-phenylenediamine derivatives and methods thereof arebeing popularly researched and developed now.

SUMMARY OF THE INVENTION

(HAA)

The present invention has been made in view of the above situation. Anobject of the present invention is to provide a halogen-containingaromatic acid dianhydride useful for raw materials of resins excellentin heat resistance, chemical resistance, water repellent property andlow dielectric property.

The present object has been achieved by a halogen-containing aromaticacid dianhydride represented by the formula 1:

wherein X is a chlorine, bromine or iodine atom, m an integer of 1 to 4,n an integer of 0 to 3, and the sum of n and m 4.(HTC)

The present invention has been achieved in view of the above situation.An object of the present invention is to provide a halogen-containingaromatic tetracarboxylic acid and a halogen-containing aromatictetranitrile compound, which are useful for raw materials ofhalogen-containing aromatic acid dianhydrides, and a method for theproduction thereof.

As a result of diligent investigations regarding raw materials used inthe production for such halogen-containing aromatic acid dianhydrides,we have found that such dianhydrides can be produced in a high yield byhydrolyzing a halogen-containing aromatic tetranitrile compound having aspecified structure and then dehydrating the resultinghalogen-containing aromatic tetracarboxylic acid. In addition, as aresult of diligent investigations regarding raw materials used in theproduction for such a halogen-containing aromatic tetranitrile compound,we have found that the halogen-containing aromatic tetranitrile compoundcan be suitably used, which compound is obtained by the reaction oftetrafluorophthalonitrile and a hydroquinone derivative having aspecified structure.

The objects of the present invention have been achieved by the following1 to 5.

-   (1) A halogen-containing aromatic tetranitrile compound represented    by the formula 21:

wherein X is a chlorine, bromine or iodine atom, m an integer of 1 to 4,n an integer of 0 to 3, and the sum of n and m 4.

-   (2) A halogen-containing aromatic tetracarboxylic acid represented    by the formula 22:

wherein X is a chlorine, bromine or iodine atom, m an integer of 1 to 4,n an integer of 0 to 3, and the sum of n and m 4.

-   (3) A method for producing a halogen-containing tetranitrile    compound represented by the formula 21, characterized by reacting    tetrafluorophthalonitrile with a hydroquinone derivative represented    by the formula 23:

wherein X is a chlorine, bromine or iodine atom, m an integer of 1 to 4,n an integer of 0 to 3, and the sum of n and m 4.

-   (4) A method for producing a halogen-containing tetracarboxylic acid    represented by the formula 22, characterized by hydrolyzing a    halogen-containing aromatic tetranitrile compound represented by the    formula 21.-   (5) A method for producing a halogen-containing aromatic    tetracarboxylic acid dianhydride represented by the formula 1:

wherein X is a chlorine, bromine or iodine atom, m an integer of 1 to 4,n an integer of 0 to 3, and the sum of n and m 4, characterized bydehydrating a halogen-containing aromatic tetracarboxylic acidrepresented by the formula 22.(HPC)

An object of the present invention is to provide a new halogenatedm-phenylenediamine compound.

The object of the present invention has been achieved by a halogenatedm-phenylenediamine compound represented by the formula 31:

wherein X is a chlorine or bromine atom, m an integer of 1 to 3, n aninteger of 3 to 1, and the sum of n and m 4.(Fluorine Compound)

An object of the present invention is to provide a new fluorine compoundused for producing m-phenylenediamine derivatives.

The object of the present invention has been achieved by a fluorinecompound represented by the formula 41:

wherein Y¹ and Y² are independently a carboxyl or cyano group, m is aninteger of 1 to 3, n an integer of 3 to 1, and the sum of n and m 4.

The above and other objects, features and advantages of the presentinvention will become clear from the following description of thepreferred embodiments.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawing incorporated in and forming a part of thespecification, illustrates several aspects of the present invention, andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1 shows a graph of ¹⁹F-NMR spectrum for1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobehzene dianhydrideobtained in Example 1 of the present invention;

FIG. 2 shows a graph of ¹⁹F-NMR spectrum for1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene obtained inExample II-1;

FIG. 3 shows a graph of ¹⁹F-NMR spectrum for1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene obtained inExample II-2;

FIG. 4 shows a graph of ¹⁹F-NMR spectrum for4-bromo-2,5,6-trifluoroisophthalonitrile obtained in Synthesis ExampleIII-1;

FIG. 5 shows a graph of ¹⁹F-NMR spectrum for4-bromo-2,5,6-trifluoroisophthalic acid obtained in Synthesis ExampleIII-4;

FIG. 6 shows a graph of ¹⁹F-NMR spectrum for5-chloro-2,4,6-trifluoro-m-phenylenediamine obtained in Example III-1;

FIG. 7 shows a graph of ¹⁹F-NMR spectrum for4-bromo-2,5,6-trifluoro-m-phenylenediamine obtained in Example III-2;

FIG. 8 shows a graph of ¹⁹F-NMR spectrum for4-bromo-2,5,6-trifluoroisophtharonitrile obtained in Example IV-1; and

FIG. 9 shows a graph of ¹⁹F-NMR spectrum for4-bromo-2,5,6-trifluoroisophthalic acid obtained in Example IV-2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(HAA)

In view of diligent investigations regarding several kinds of materials,we have known that the halogen-containing aromatic acid dianhydridehaving a specified structure excels in heat resistance, chemicalresistance, water repellent property and low dielectric property, andtherefore is useful for intermediate raw materials for wiring baseplate, photosensitive and liquid crystal materials. Such a structure isthat all C—H bonds in the phthalic anhydride portions in both sides ofthe dianhydride are substituted with C—F bonds, and all C—H group in thebenzene ring in the central portion thereof substituted with C-otherhalogen atom groups than F, partially including C—F group. Based on theabove knowledge, we have completed the present invention.

The present invention relates to a new halogen-containing aromatic aciddianhydride represented by the formula 1 (hereinafter it is referred toas “HAA”).

In the formula 1, X is a chlorine, bromine or iodine atom, preferablychlorine or bromine atom, and most preferably chlorine atom. The term mindicates the bonding number of X to the benzene ring, an integer of 1to 4, preferably an integer of 2 to 4, and most preferably 4. The term nindicates the bonding number of fluorine atom to the benzene ring, aninteger of 3 to 0, preferably an integer of 2 to 0, and most preferably0. In the formula 1, the sum of n and m is 4.

The HAA preferably includes a compound represented by the formula:

more preferably 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzenedianhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrabromobenzenedianhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-chlorotrifluorobenzene dianhydride,1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-bromotrifluorob enzenedianhydride, and most preferably1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride.

The HAA is represented by a combination of p-phenyldioxy grouprepresented by the formula:

with trifluorophenyl group represented by the formula:

The HAA can be produced in a combination of known methods. Theproduction method of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride asthe representative will be explained below. Other HAAs of the presentinvention can be produced in the similar manner as the above, using, intetrachlorohydroquinone (or its metal salts such as 2 Na salt), thecorresponding halogen atom instead of the chlorine atom.

The objective 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzenedianhydride is produced as an embodiment by reactingtetrafluorophthalonitrile and tetrachlorohydroquinone (or its metalsalts such as 2 Na salt; it is summarized as “tetrachlorohydroquinone”)in the presence of a base in a solvent at a temperature of −20° C. to200° C. for 0.1 to 20 hours to form1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene (Step 1a);hydrolyzing the resulting1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene with an acid at atemperature of 50° C. to 300° C. for 0.5 to 20 hours to form1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (Step 1b);dissolving the reaction solution including1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene in a mediumcontaining an organic solvent once, purifying and separating the producttherefrom (Step 1c); and then dehydrating the separated1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (Step 1d).

Now each step will be explained in turn.

As the base to be used in Step 1a, there can be cited an alkali metalsalt, such as potassium fluoride, sodium fluoride, lithium fluoride,potassium chloride, sodium chloride and lithium chloride; an alkaliearth metal salt such as calcium chloride and magnesium chloride; acarbonate of alkali metals such as sodium hydrogen carbonate, lithiumhydrogen carbonate, potassium hydrogen carbonate, sodium carbonate,lithium carbonate and potassium carbonate; a carbonate of alkali earthmetals such as calcium carbonate and magnesium carbonate; a tertiaryamine such as trimethylamine, triethylamine, tripropylamine,tributylamine, tricyclohexylamine, tribenzylamine, triphenylamine andpyridine, and preferably potassium fluoride, sodium carbonate, potassiumcarbonate, triethylamine, tripropylamine and pyridine. The base can beadded in order to effectively proceed with the reaction oftetrafluorophthalonitrile and tetrachlorohydroquinone. The base is addedusually in the range of 0.5 to 20 mol %, preferably 2 to 10 mol %, basedon the amount of tetrachlorohydroquinone.

As the solvent to be used in Step 1a, there can be cited nitriles suchas acetonitrile and benzonitrile; ketones such as methylisobutylketone(MIBK), methylethylketone (MEK) and cyclohexanone; halogenatedhydrocarbons such as chloroform, methylene chloride, carbontetrachloride, chloroethane and di-, tri- and tetra-chloroethane;aromatic hydrocarbons such as benzene, toluene and xylene; hydrocarbonssuch as pentane, hexane, cyclohexane and heptane; ethers such asdiethylether, isopropylether, tetrahydrofuran (THF), dioxane,diphenylether, benzylether and tert-butylether; esters such as methylformate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate,and isopropyl acetate; N-methylpyrrolidinone (NMP), dimethylformamide(DMF), dimethylsulfoxide (DMSO) and dimethylacetamide, and preferablyacetonitrile, MIBK, NMP, DMF and DMSO. The solvent can be added in orderto effectively proceed with the reaction. For instance,tetrafluorophthalonitrile may be in the range of 1 to 80% by weight, andpreferably 5 to 50% by weight, based on the weight of the solvent.

The mixing ratio of tetrafluorophthalonitrile to tetrachlorohydroquinoneis stoichiometrically 2:1 (molar ratio). The mixing ratio may be usuallyby molar ratio in the range of 2:1 to 100:1, and preferably 2:1 to 50:1in view of reaction efficiency and reaction selectivity.

As the acid to be used in Step 1b, there can be cited sulfuric acid,hydrochloric acid, phosphoric acid or oxalic acid in the form of as itis or an aqueous solution (acid solution). In the case of the acidsolution, it is necessary to fully hydrolyze1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene. The acidconcentration may be in the range of 0.40 to 85% by weight depending onreaction temperatures, and kinds of acids. In the case of sulfuric acid,the acid concentration in aqueous sulfuric acid solution is preferablyin the range of 50 to 80% by weight. The acid can be added to fullyhydrolyzing 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene. Theconcentration of 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzeneto the acid to be added may be usually in the range of 1 to 60% byweight, and preferably in the range of 5 to 50% by weight depending onreaction temperatures and kinds of acids.

As concrete examples for Step 1c, there can be cited a method in whichto the resulting product in Step 1b are poured an organic solvent ofcapable of forming two layers with the water to dissolve the productinto the organic solvent, and then the organic layer is separated,evaporated to dryness. By this method, phthalamide derivatives intowhich 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene has beenincorporated, can be deposited on the surface of solids. Suitableorganic solvents should form a two-layer state with water, and not reactthe products, but for example include fatty acid esters, ketones,ethers, and benzonitriles, more preferably fatty acid esters andketones, and most preferably ethyl acetate, isopropyl acetate,methylisobutylketone. The solvent can be added to effectively dissolvethe products or more. Then, the organic layer is separated from thesolution, and may be washed with water if necessary.

As other examples for Step 1c, there can be cited methods; in Step 1b,to 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene as theresidue, are poured an organic solvent and water to dissolve the residueinto the organic solvent, the organic layer is separated if the organicsolvent forms a two-layer state with water, and then evaporated todryness to produce an objective material; alternatively if the organicsolvent added and water do not form a two-layer state, filtration isperformed till solids precipitate by adding water, followed by dryingthereby producing an objective product. In this case, organic solventsthat form a two-layer state, are the same as the above solvent. Organicsolvents should not form a two-layer state, and not react the products,but for example include ketones such as acetone, acetonitriles such asacetonitrile, and alcohols such as methanol and ethanol, and preferablyketons. Otherwise, the organic solvents that do not form a two-layerstate should be added to effectively dissolve the products or more.Then, water is added to precipitate solids, the resulting solid isfiltrated, dried to obtain a product. In this case, water should beadded to effectively precipitate the solid or more, and may be fivetimes in weight if the organic solvent is acetone.

In the first embodiment, Steps 1b and 1c are performed at least one. Ifthese steps are repeated, it is preferably performed in the state ofcombination of Steps 1b and 1c, but Step 1b or Step 1c may beindependently repeated if necessary. Suitable repeating numbers compriseusually 2 to 10 times, and preferably 3 to 6 times. In this case, Steps1b and 1c may be performed in the same or different conditions.

In Step 1d, dehydration may be performed according to known methods: (1)dehydration is performed at 0° C. to 200° C. for 0.5 to 50 hours indehydration agents such as thionyl chloride, sulfuric acid, concentratedsulfuric acid, phosphoric acid, metaphosphoric acid, polyphosphoricacid, anhydrous hydrofluoric acid, P₂O₅, sodium hydrogen sulfate,anhydrous zinc chloride, phosphorus oxychloride, acetic anhydride,acetyl chloride, oxalic acid, sulfonic acid and phthalic anhydride; (2)a gas phase catalytic reaction is performed using dehydration catalystssuch as alumina catalysts, phosphoric acid or phosphate, which isdeposited on inert carriers such as diatomaceous earth, silica-aluminacatalysts and activated clay; (3) heating is performed at a temperatureof 150° C. to 300° C. in the state of non-aqueous solution or solidstate. Among them, the above (1) is prefer in which dehydration isperformed at a temperature of 50° C. to 200° C. for 0.1 to 20 hours inthe dehydration agents such as thionyl chloride, phosphoric acid,polyphosphoric acid, acetic anhydride and phthalic anhydride.

Alternatively, in the first embodiment, the objective1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride canbe directly synthesized by simultaneous hydrolysis and dehydration byheating 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene in anacid at 100° C. to 300° C. for 5 to 40 hours. In this case, the acid maybe cited as the same as the above.

On the other hand, the objective1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride canbe produced in accordance with the method described in JP-A-9-110,784.To put it simply, the objective is produced in a highly pure and yieldsby in the same manner as the first embodiment, synthesizing1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene (Step 1a′),heating the resultant in an acid or aqueous acidic medium to form aproduct including1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (Step 1b′),adding an alkaline substance to the reaction solution to be alkaline andheating (Step 1c′), then adding an acidic substance into this alkalineproduct solution to be acidic to separate1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene in high pure(Step 1d′), and dehydrating the product (Step 1e′).

The HAA has a relatively high melting point, and low solubility intodimethylacetoamide, thus excels in heat resistance and chemicalresistance.

In accordance with the present invention, since HAA excels in heatresistance, chemical resistance, water repellent property and lowdielectric property, it is expected to be useful for intermediatematerials for wiring base plate, photosensitive and liquid crystalmaterials.

(HTC)

In a first aspect, the present invention relates to a newhalogen-containing aromatic tetranitrile compound represented by theformula 21 (hereinafter it is referred to as “HTC”).

In the formula 21, X is a chlorine, bromine or iodine atom, preferablychlorine or bromine atom, and most preferably chlorine atom. The term mindicates the bonding number of X to the central benzene ring withoutcyano groups, an integer of 1 to 4, preferably an integer of 2 to 4, andmost preferably 4. The term n indicates the bonding number of fluorineatom to the central benzene ring without cyano groups, an integer of 3to 0, preferably an integer of 2 to 0, and most preferably 0. In theformula 21, the sum of n and m is 4.

The HTC preferably includes a compound represented by the formula:

more preferably 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene,1,4-bis(3,4-dicyanotrifluorophenoxy)tetrabromobenzene,1,4-bis(3,4-dicyanotrifluorophenoxy)-2-chlorotrifluorobe nzene, and1,4-bis(3,4-dicyanotrifluorophenoxy)-2-bromotrifluoroben zene, and mostpreferably 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene.

The HTC is represented as the combination of p-phenyldioxy grouprepresented by the formula:

and dicyanotrifluorophenyl group represented by the formula:

The HTC can be produced in a combination of known methods, preferably bythe reaction of tetrafluorophthalonitrile and a hydroquinone derivativerepresented by the formula 23. In a second aspect, the present inventionrelates to a method for producing a HTC by means of the reaction oftetrafluorophthalonitrile with a hydroquinone derivative represented bythe formula 23 (hereinafter it may be referred to as “hydroquinonederivative”). In the formula 23, X, m, and n mean the same as those inthe formula 21.

Hydroquinone derivatives to be used in the second aspect, may beappropriately selected, depending on the kinds of the HTC, preferablyfrom tetrachlorohydroquinone, tetrabromohydroquinone,2-chloro-3,5,6-trifluorohydroquinone,2-bromo-3,5,6-trifluorohydroquinone, or metal salts such as 2 sodiumsalt and 2 potassium salt, and most preferably tetrachlorohydroquinoneand its 2 sodium salt. The hydroquinone derivative may be theoreticallyused in one mole based on two moles of tetrafluorophthalonitrile as theother raw material. In consideration of reaction efficiency and reactionselectivity, excess tetrafluorophthalonitrile should be preferablypresent. Concretely, the hydroquinone derivative may be preferably inthe range of 1 to 50 moles, and more preferably in the range of 2 to 50moles, per 100 moles of tetrafluorophthalonitrile.

In the second aspect, the reaction of tetrafluorophthalonitrile and thehydroquinone derivative is preferably performed in the presence of abase, in consideration of reaction efficiency. In this case, suitablebases include an alkali metal salt such as potassium fluoride, sodiumfluoride, lithium fluoride, potassium chloride, sodium chloride, andlithium chloride; an alkaline earth metal salt such as calcium chlorideand magnesium chloride; a carbonate of alkali metals such as sodiumhydrogen carbonate, lithium hydrogen carbonate, potassium hydrogencarbonate, sodium carbonate, lithium carbonate and potassium carbonate;a carbonate of alkaline earth metals such as calcium carbonate andmagnesium carbonate; a tertiary amine such as trimethylamine,triethylamine, tripropylamine, tributylamine, tricyclohexylamine,tribenzylamine, triphenylamine, and pyridine; and preferably potassiumfluoride, sodium carbonate, potassium carbonate, triethylamine,tripropylamine and pyridine. The base may be added in order toeffectively proceed with the reaction of tetrafluorophthalonitrile andthe hydroquinone derivative, but for example usually in the range of 0.5to 20 mol %, and preferably in the range of 2 to 10 mol %, based on theamount of the hydroquinone derivative.

Further, in the second aspect, the reaction of tetrafluorophthalonitrileand the hydroquinone derivative may be performed in the presence orabsence of a solvent. Suitable solvents include nitrites such asacetonitrile and benzonitrile; ketones such as acetone,methylisobutylketone (MIBK), methylethylketone (MEK) and cyclohexanone;halogenated hydrocarbons such as chloroform, methylene chloride, carbontetrachloride, chloroethane and di-, tri- and tetra-chloroethane;aromatic hydrocarbons such as benzene toluene and xylene; hydrocarbonssuch as pentane, hexane, cyclohexane and heptane; ethers such asdiethylether, isopropylether, tetrahydrofuran (THF), dioxane,diphenylether, benzylether and tert-butylether; esters such as methylformate, ethyl formate, methyl acetate, ethyl acetate, propyl acetateand isopropyl acetate, N-methylpyrrolidinone (NMP), dimethylformamide(DMF), dimethylsulfoxide (DMSO) and dimethylacetamide, and preferablyacetonitrile, MIBK, NMP, DMF and DMSO. The solvent may be added in orderto effectively proceed with the reaction, but usually in such a way thattetrafluorophthalonitrile is in the range of 1 to 80% by weight, andpreferably in the range of 5 to 50% by weight, based on the weight ofthe solvent.

In the second aspect, the reaction condition oftetrafluorophthalonitrile and the hydroquinone derivative may beappropriately selected so as to proceed with the reaction effectively,but for example suitable reaction temperatures are usually in the rangeof −50° C. to 300° C., and preferably in the range of −20° C. to 200°C., and suitable reaction times usually in the range of 0.1 to 40 hours,and preferably 0.1 to 20 hours. The reaction may be performed in theconditions of a reduced, normal or compressed pressure, and preferablynormal pressure in view of equipment.

In the second aspect, hydrogen fluoride generated by the reaction oftetrafluorophthalonitrile and the hydroquinone derivative may bepreferably removed by conventional methods: after reaction, the HTC isextracted with a non-aqueous organic solvent, and then washed withwater; and in advance, a base is added into the reaction system to trapthe hydrogen fluoride as the salt. Suitable non-aqueous organic solventsin the first method, include ketones such as MIBK, MEK andcyclohexanone; halogenated hydrocarbons such as chloroform, methylenechloride, carbon tetrachloride, chloroethane and di-, tri- andtetra-chloroethane; aromatic hydrocarbons such as benzene, toluene andxylene; hydrocarbons such as pentane, hexane, cyclohexane and heptane;ethers such as diethylether, isopropylether, diphenylether, benzylether,tert-butylether; esters such as methyl formate ethyl formate, methylacetate, ethyl acetate, propyl acetate, isopropyl acetate, andpreferably MIBK, MEK and isopropylether and ethyl acetate. In the secondmethod, suitable bases include a calcium compound such as calciumchloride and calcium carbonate; a tertiary amine such as trimethylamine,triethylamine, tripropylamine, tributylamine, tricyclohexylamine,tribenzylamine, triphenylamine and pyridine, and preferably calciumcompounds. When calcium compounds are used, it can react with hydrogenfluoride to form calcium fluoride (CaF₂) as precipitates, which can bereadily removed for example by filtration.

In a third aspect, the present invention relates to a newhalogen-containing aromatic tetracarboxylic acid represented by theformula 22 (hereinafter it is referred to as “HTA”). The HTA isrepresented, in the same manner as the first aspect, as a combination ofp-phenyldioxy group represented by the above formula withdicarboxytrifluorophenyl group represented by the formula:

In the formula 22, X, m and n are the same as those defined in formula21.

Suitable HTAs include a compound represented by the formula:

preferably 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene,1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrabromobenzene,1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-chlorotrifluoro benzene, and1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-bromotrifluorob enzene, andmost preferably1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene.

The HTA of the present invention can be produced by a combination ofknown methods, preferably by hydrolyzing the HTC of the first aspect ofthe present invention. In accordance with a fourth aspect of the presentinvention, it relates to a method for producing HTA as the third aspectof the present invention by hydrolyzing the HTC as the first aspect ofthe present invention.

In the fourth aspect, the HTC may be hydrolyzed preferably in thepresence of an acid, and more preferably in the presence of the acid inan organic solvent. Suitable acids include sulfuric acid, hydrochloricacid, phosphoric acid and oxalic acid in the form of acid itself or anaqueous solution. In the case of the aqueous solution, the acidconcentration should fully hydrolyze HTC, but be for example in therange of 40 to 85% by weight depending on the kinds of reactiontemperatures and acids. Among them, sulfuric acid, in particular anaqueous 50 to 80% by weight sulfuric acid solution is preferable. Theacid may be added so as to fully hydrolyze the HTC, but usually theconcentration of HTC to the acid to be added may be in the range of 1 to60% by weight, and preferably in the range of 5 to 50% by weight.

The organic solvent to be used in the fourth aspect, should dissolveHTC, but for example include-inorganic or organic acids. For example, itcan be cited organic acids such as formic acid, acetic acid andpropionic acid; acid anhydrides such as formic anhydride, aceticanhydride and propionic anhydride; nitriles such as acetonitrile andbenzonitrile; ketones such as acetone, MIBK, MEK and cyclohexanone;halogenated hydrocarbons such as chloroform, methylene chloride, carbontetrachloride, chloroethane and di-, tri- and tetra-chloroethane;aromatic hydrocarbons such as benzene, toluene and xylene; hydrocarbonssuch as pentane, hexane, cyclohexanone and heptane; ethers such asdiethylether, isopropylether, THF, dioxane, diphenylether, benzyletherand tert-butylether; esters such as methyl formate, ethyl formate,methyl acetate, ethyl acetate, propyl acetate and isopropyl acetate;NMP, DMF, DMSO and dimethylacetamide, preferably an organic acid andacid anhydride, and most preferably acetic acid, propionic acid, aceticanhydride and propionic anhydride. The organic solvent may be added soas to fully dissolve the HTC, but the concentration of the HTC isusually in the range of 1 to 60% by weight, and preferably in the rangeof 5 to 50% by weight, based on the weight of the organic solvent. Inthe present invention, the organic solvent may include water unless itblocks the dissolution of the HTC and the hydrolysis by acids.

In the fourth aspect, HTC, acids and organic solvents are arbitrarilymixed for example in a lump, the HTC is dissolved in the organicsolvent, and then the acid is added therein; or the organic solvent andacid are mixed and then the HTC added therein. In order to effectivelyhydrolyze the HTC with the acid, it is preferred to dissolve the HTCinto the organic solvent to form a uniform solution, and then to thissolution is added the acid. In the conventional method for hydrolyzingthe HTC using the acid alone, plural of hydrolysis steps using acidsmust be repeated so as to heighten the purity of the objective product,since the dissolving of the raw material into the aqueous acid solutionis not sufficient, fully hydrolysis is not performed and thus the purityof the objective product is not fully improved. It is found that, whenthe HTC is dissolved in advance and then hydrolysis is performed bymeans of acids, a halogen-containing aromatic compound having aprescribed purity can be obtained at one time by means of hydrolysis byacids. In order to effectively hydrolyze the HTC with acids in theorganic solvent, it is preferred to add the acids while stirring thetetranitrile solution.

In the present invention, suitable hydrolysis conditions of the HTC arefully hydrolyze the HTC for example that the hydrolysis temperature ispreferably in the range of 20° C. to 300° C., and more-preferably in therange of 50° C. to 200° C., and the hydrolysis duration usually in therange of 0.1 to 40 hours, and preferably 0.5 to 20 hours.

One embodiment of the fourth aspect of the present invention has beenexplained as above, but the present method is not restricted to theabove method. Now, another embodiment of the fourth aspect of thepresent invention will be explained below.

In accordance with another embodiment of the fourth aspect of thepresent invention, HTC is heated in an aqueous acidic medium to obtain areactant solution including the corresponding HTA (Step 2a); to thisreactant solution is added an alkali substance to alkali and heating isperformed (Step 2b); and then to the alkali reactant solution is addedan acidic substance to acidic, the objective HTA is separated from thesolution (Step 2c). In accordance with this method, the objective HTAhaving a high purity can be produced.

Next, each step will be explained in turn.

In Step 2a, the HTC may be poured together with an aqueous acidic mediumor into the aqueous acidic medium one by one. In the latter case, theHTC may be added in the form of powder as it is, or solutions of such asacetic anhydride, propionic anhydride and acetonitrile. Suitable aqueousacidic medium include an aqueous organic or inorganic solution ofcapable of changing cyano (—CN) group to carboxyl (—COOH) group, andpreferably an aqueous solution of inorganic acids such as phosphorousacid, sulfuric acid and hydrochloric acid. Among them, an aqueoussulfuric acid solution, usually in the acid concentration of 40 to 85%by weight, and preferably in the acid concentration of 50 to 80% byweight, is preferable in view of high yields. The HTC may be added so asto produce the objective product in a high yield, but preferably in therange of 5 to 50% by weight, based on the weight of the aqueous acidicmedium. Suitable reaction conditions in accordance with the embodimentof the present invention are to produce the objective product in a highyield, but suitable reaction temperatures are in the range of 120° C. to180° C., and preferably in the range of 140° C. to 170° C., and suitablereaction durations are usually in the range of 1 to 24 hours dependingon the reaction temperature. After the completion of reaction, the HTAis precipitated in the reactant solution, and the reactant solution maybe used as it is or after separation, residues may be used.

In Step 2b, in using the reactant solution containing the HTA as it is,to the reactant solution is added an alkali substance in the form ofsolid, vapor or an aqueous solution. On the other hand, in using the HTAas the residue, to the residue is added water if necessary, and thenadded an alkali substance in the form of solid, vapor or an aqueoussolution. Suitable alkali substances include a hydroxide of alkalimetals such as sodium hydroxide and potassium hydroxide; a carbonate ofalkali metals such as sodium carbonate and potassium carbonate; abicarbonate of alkali metals such as sodium bicarbonate and potassiumbicarbonate; a hydroxide of alkaline earth metals such as magnesiumhydroxide, calcium hydroxide, strontium hydroxide and barium hydroxide;a carbonate of alkaline earth metals such as magnesium carbonate,calcium carbonate, strontium carbonate and barium carbonate; abicarbonate of alkaline earth metals such as magnesium bicarbonate,calcium bicarbonate, strontium bicarbonate and barium bicarbonate; andammonia, preferably a hydroxide of alkali metals, a carbonate of alkalimetals, a bicarbonate of alkali metals, and most preferably a hydroxideof alkali metals. The alkali substance may be added singly or in acombination thereof. The alkali substance may be added so as to obtainthe objective product in a high yield, but preferably adjust the pH ofthe reaction solution in the range of 9.5 to 12.5, and more preferablyin the range of 11.0 to 12.0. The amount of the alkali substance in thecase of adjusting the pH corresponds to preferably the sum of the amountof the alkali substance to neutralize the acid in the aqueous acidicmedium used in Step 2a, and the amount of the alkali substance in therange of 3.5 to 4.5 mol, and preferably 3.8 to 4.2 mol as monovalentbased on the HTA used in the reaction. Suitable reaction conditions areappropriately selected so as to obtain the objective product inefficiently and having a high yield, but suitable temperatures areusually in the range of 30° C. to 150° C., and preferably in the rangeof 70° C. to 130° C., suitable reaction durations are usually less than8 hours, and preferably in the range of 1 to 6 hours.

In Step 2c, an acidic substance may be added so as to acidify thereactant solution, but for example include an organic or inorganic acid,and preferably an inorganic acid such as sulfuric acid, hydrochloricacid and phosphoric acid. Suitable acidic substance may be added as itis or may be added in the form of solutions using water or the like, butinclude more preferably in the form of an aqueous sulfuric acidsolution. The sulfuric acid concentration in the aqueous solution ispreferably in the range of 1 to 50% by weight. Suitable acidicsubstances may be added so as to acidify the carboxyl groups neutralizedby the alkali substance in Step 2b or more. Usually, the acidicsubstance may be added to acidify the corresponding alkali substanceamount, which is obtained by reducing the amount necessary to beneutralized with the acid from the total alkali amount used in Step 2b,or more. The acidic substance may be added into the alkali reactantsolution in a singly or sequentially.

After addition of the acidic substance, if the objective tetracarboxylicacid salt is a salt, which is easily dissolved into water, such assodium sulfate, potassium sulfate, ammonium sulfate and sodium chloride,the salt can be separated readily by filtration, extraction or the like.If the salt of the objective product, after addition of the acidicsubstance, is a salt, which is difficult to dissolve in water, the saltcan be separated by means of extraction or the like. In the case offiltration, after filtration the residue is washed with an appropriateamount of water to preferably remove the acidic substance added and thesalt formed. In the case of extraction, after dissolving the objectiveproduct with a suitable solvent, the objective product is separated byseparating the solution therefrom in that the resulting salt is asolution, or by filtrating and separating the solution in that theresulting salt is precipitated. After separating the solution, theproduct is preferably washed with an approximate amount of water toremove the acid added and the salt formed in view of purity of theobjective product. Suitable solvents to be used in this case should forma two-layer state and further dissolve the objective product, but forexample include fatty acid esters, ketones, ethers and benzonitriles,and more preferably fatty acid esters and ketons. Concretely, ethylacetate, isopropyl acetate, methylisopropylketone ormethylisobutylketone is preferable.

In accordance with other embodiments of the fourth aspect, HTC is heatedin an acidic medium to obtain a reactant solution containing thecorresponding HTA (Step 2a); then this reactant solution is dissolved ina medium containing organic solvents once and the product is separatedfrom the medium (Step 2b′); at least two of Steps 2a to 2b′ to separatethe HTA from the reactant solution (Step 2c). In accordance with thismethod, the objective HTA can be obtained in a high purity. In thisembodiment, Step 2a is the same as the above.

As an concrete example for Step 2b′, there can be cited a method forprecipitating on the surface of solids a phthalamide derivativeincorporated into the HTA by adding an organic solvent into the reactantsolution produced in Step 2a to form a two-layer state, dissolving theproduct into the organic solvent, then separating the solution, and thenevaporating the solution to dryness. Suitable organic solvents form atwo-layer state with water, and do not react with the product, but forinstance include fatty acid esters, ketones, ethers and benzonitriles,and preferably fatty acid esters and ketones. For example, ethylacetate, isopropyl acetate or methylisobutylketone are preferable. Theorganic solvent is used to dissolve the product or more. Subsequently,the organic layer is separated from the medium and washed with water ifnecessary.

In using the HTA in Step 2a as the residue, to the residue are added anorganic solvent and water to dissolve the residue into the organicsolvent. If the organic layer forms a two-layer state, the organic layeris separated and evaporated to dryness, thereby obtaining the objectiveproduct; or if the organic solvent added does not form a two-layerstate, water is added till solids precipitate, the precipitate isfiltrated and dried to dryness. In this case, the organic solvent whichform a two-layer state, is the same as the above. The organic solventwhich does not form a two-layer state, should does not react with theproduct, but for example include ketones such as acetone; acetonitrilessuch as acetonitrile; alcohols such as methanol and ethanol, andpreferably ketons. The organic solvent which does not form a two-layerstate with water is added to dissolve the product or more. Subsequently,water is added till solids precipitate, and the product is obtained byfiltration and dryness. Water is added to precipitate the solids ormore, but for example five times or more at volume if the organicsolvent is acetone.

Steps 2a to 2b′ may be repeated more than two, usually 2 to 10 times,and preferably 3 to 6 times. Each step 2a and step 2b′ may be same ornot in each step.

The HTA thus obtained is dehydrated to produce the corresponding HAA. Inaccordance with a five aspect of the present invention, it can providesa method for producing a HAA represented by the formula 1 by dehydratingthe HTA as the third aspect of the present invention.

In the fifth aspect, HTA can be dehydrated in known methods, for example(21) dehydration is performed at 0° C. to 200° C. for 0.5 to 50 hours indehydration agents such as thionyl chloride, sulfuric acid, concentratedsulfuric acid, phosphoric acid, metaphosphoric acid, polyphosphoricacid, anhydrous hydrofluoric acid, P₂O₅, sodium hydrogen sulfate,anhydrous zinc chloride, phosphorus oxychloride, acetic anhydride,acetyl chloride, oxalic acid, sulfonic acid and phthalic anhydride; (22)a gas phase catalytic reaction is performed using dehydration catalystssuch as alumina catalysts, phosphoric acid or phosphate, which isdeposited on inert carriers such as diatomaceous earth, silica-aluminacatalysts and activated clay; (23) heating is performed at a temperatureof 150° C. to 300° C. in the state of non-aqueous solution or solidstate. Among them, the above (21) is prefer in which dehydration isperformed at a temperature of 50° C. to 200° C. for 0.1 to 20 hours inthe dehydration agents such as thionyl chloride, phosphoric acid,polyphosphoric acid, acetic anhydride and phthalic anhydride.

The objective halogen-containing aromatic tetracarboxylic aciddianhydride can be directly synthesized by heating1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene at a temperaturerange of 100° C. to 300° C. for 0.5 to 40 hours by performing hydrolysisand dehydration at the same time. The HTA and HTC are useful for the rawmaterials of the corresponding HAA.

(HPC)

The present invention provides a halogenated m-phenylenediamine compoundrepresented by the formula 31 (hereinafter it is referred to as “HPC”):

In the formula 31, X is a chlorine or bromine atom, may be identical ordifferent from each other if X is present in a state of plural (namely nis 2 or 3), n indicates the bonding number of X to the benzene ring, aninteger of 1 to 3, preferably an integer of 1 or 2, and mostpreferably 1. The position of X to the benzene ring depends on thebonding number and kinds of X, and a prescribed property offluorine-containing compounds, but is preferably 4 or 5 if n is one, and4 and 6 if n is two.

Further, in the formula 31, m indicates the bonding number of fluorineatom to the benzene ring, an integer of 3 to 1, preferably an integer of3 or 2, and most preferably an integer of 3. The sum of n and m is 4 inthe formula 31. In other words, the halogenated m-phenylenediamine has acompound without carbon-hydrogen bonds.

Suitable halogenated m-phenylenediamine compound of the presentinvention preferably include 4-bromo-2,5,6-trifluoro-m-phenylenediamine,4-chloro-2,5,6-trifluoro-m-phenylenediamine,5-bromo-2,4,6-trifluoro-m-phenylenediamine,5-chloro-2,4,6-trifluoro-m-phenylenediamine,4,6-dibromo-2,5-difluoro-m-phenylenediamine, and4,6-dichloro-2,5-difluoro-m-phenylenediamine, more preferably4-bromo-2,5,6-trifluoro-m-phenylenediamine,4-chloro-2,5,6-trifluoro-m-phenylenediamine,5-chloro-2,4,6-trifluoro-m-phenylenediamine, and5-bromo-2,4,6-trifluoro-m-phenylenediamine.

The HPC of the present invention can be produced by applying a knownmethod as follows.

In accordance with an embodiment, the objective HPC can be produced byforming halogenated trifluoroisophthalonitrile (3a); forming ahalogenated trifluoroisophthalic acid from the halogenatedtrifluoroisophthalonitrile (3b); reacting this halogenatedtrifluoroisophthalic acid with an azide compound in the presence of aLewis base in a solvent to form an acid azide, thermal rearranging andhydrolyzing this acid azide (3c). In this specification, the term“halogenated trifluoroisophthalonitrile” means a compound in which both—NH₂ groups in the HPC of the present invention are substituted with —CNgroups, and the term “halogenated trifluoroisophthalic acid” means acompound in which both —NH₂ groups in the HPC thereof are substitutedwith —COOH groups.

Step 3a in an embodiment of the HPC of the present invention will beexplained as follows.

Halogenated trifluoroisophthalonitrile is produced in a known method,for example the method described in JP-B-63-5023.

A first embodiment for producing a halogenatedtrifluoroisophthalonitrile of the present invention will be explainedbelow. In accordance with the first embodiment,tetrafluoroisophthalonitrile is reacted with a brominating orchlorinating agent (hereinafter it may be referred to as “halogenatingagent”.) to replace the fluorine atoms bonded to the benzene ring withbromine or chlorine atom. For example, by specifically substituting thefluorine at the 4-position in tetrafluoroisophthalonitrile,4-bromo-2,5,6-trifluoroisophthalonitrile or4-chloro-2,5,6-trifluoroisophthalonitrile can be obtained in a highyield.

In the first embodiment, suitable brominating agents include knownbrominating agents, but for example sodium bromide, potassium bromideand lithium bromide. Sodium bromide and potassium bromide are preferablein view of readily handling and availability.

In the first embodiment, suitable chlorinating agents include knownchlorinating agents, but for example sodium chloride, potassium chlorideand lithium chloride. Sodium chloride and potassium chloride arepreferable in view of readily handling and availability.

In the first embodiment, the halogenating agent may be added tospecifically substitute the fluorine atom at the 4-position intetrafluoroisophthalonitrile with bromine or chlorine atom or more, butfor example in the range of 1 to 5 moles, and preferably in the range of1 to 2 moles, per mol of tetrafluoroisophthalonitrile. If it exceeds 5moles, there is a fear that fluorine atoms except for the 4-position intetrafluoroisophthalonitrile will be substituted with bromine orchlorine atom, and further it is necessary to treat the remaininghalogenating agent, and therefore not economically. In contrast, if itis less than 1 mole, the fluorine atom in the 4-position will not befully substituted with such an agent, and unreacted raw material willremain in a large amount.

In the first embodiment, the bromination or chlorination oftetrafluoroisophthalonitrile may be performed in the presence or absenceof a solvent, but preferably in the presence of the solvent. Suitablesolvents include those which do not block such a bromination orchlorination, and are inert for the brominating or chlorinating agent,but for example nitriles such as acetonitrile and benzonitrile; ketonessuch as acetone, methylisobutylketone (MIBK), methylethylketone (MEK)and cyclohexanone; halogenated hydrocarbons such as chloroform,methylene chloride, carbon tetrachloride, chloroethane and di-, tri- andtetra-chloroethane; aromatic hydrocarbons such as benzene, toluene andxylene; hydrocarbons such as pentane, hexane, cyclohexane and heptane;ethers such as diethylether, isopropylether, tetrahydrofuran (THF),dioxane, diphenylether, benzylether and tert-butylether; esters such asmethyl formate, ethyl formate, methyl acetate, ethyl acetate, propylacetate and isopropyl acetate; N-methylpyrrolidinone (NMP),dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide,sulfolan (TMSO₂) and dimethylsulfolan (DMSO₂); and more preferablyacetonitrile, MIBK, NMP, DMF and DMSO. The solvent may be used in such away that the concentration of tetrafluoroisophthalonitrile in thesolvent is usually in the range of 2 to 80 (w/v)%, and more preferablyin the range of 5 to 50 (w/v)%. The chlorination or bromination reactionmay be performed preferably free from water so as to improve reactionvelocity and prevent side reactions. In using solvents having a highhygroscopic property such as dimethylsulfoxide, sulfolan,dimethylformamide, N-methyl pyrrolidinone and dimethylsulfolan, benzeneor toluene is added therein preferably so as to remove the watertherefrom prior to the substitution reaction.

Tetrafluoroisophthalonitrile and the halogenating agent are reacted tofully proceed with the halogen substitution reaction, but the reactiontemperature is usually in the range of 0° C. to 300° C., and preferablyin the range of 50° C. to 250° C., and the reaction duration is usuallyin the range of 0.5 to 20 hours. The reaction may be performed under areduced, normal or a compressed pressure, and preferably at normalpressure.

In a second embodiment, a halogenated trifluoroisophthalonitrile may beproduced by fluorinating tetrachloroisophthalonitrile ortetrabromoisophthalonitrile (it may be referred to as “halogenatedisophthalonitrile”.) with a fluorinating agent. The chlorine or bromineatoms in the 2, 4, and 6 positions in halogenated isophthalonitrile arespecifically substituted with fluorine atoms by means of nucleophilicsubstitution reaction to form a desired5-chloro-2,4,6-trifluoroisophthalonitrile or5-bromo-2,4,6-trifluoroisophthalonitrile in a high yield.

In the second embodiment, suitable fluorinating agents include knownfluorinating agents, but for example potassium fluoride, cesiumfluoride, sodium fluoride, barium fluoride, calcium fluoride andantimony fluoride, and preferably potassium fluoride in view of handlingproperty and acquisition with ease.

The fluorinating agent may be added to specifically fluorinate thechlorine or bromine atoms in the 2,4,6 positions in halogenatedisophthalonitrile, but stoichiometrically three times per mole of theraw material. Concretely, the fluorinating agent is usually in the rangeof 3 to 20 moles, and preferably 3 to 10 moles, per mole of halogenatedisophthalonitrile. If it exceeds 20 moles, there is a fear that the5-position will be fluorinated, and further it is necessary to treat theremaining fluorinating agents, so that not economical. In contrast, ifit is less than 3 moles, the chlorine or bromine atoms in the 2,4,6positions are not fully fluorinated, thereby the yield of the objectiveproduct will be lowered.

The fluorinating reaction for halogenated isophthalonitrile may beperformed in the presence or absence of a solvent, but preferably in thepresence of the solvent. Suitable solvents include those which do notblock the fluorinating reaction and are inert fortetrachloroisophthalonitrile, tetrabromoisophthalonitrile and thefluorinating agents, but for example benzonitrile, DMSO, sulfolan(TMSO₂), DMF, N-methylpyrrolidinone (NMP), dimethylsulfolan (DMSO₂),acetonitrile, acetone, MEK and MIBK, and preferably benzonitrile andacetonitrile. The solvent may be used in such a way that theconcentration of halogenated isophthalonitrile is usually in the rangeof 1 to 80 (w/v) %, and preferably 5 to 50 (w/v) %. The fluorination ispreferably performed free from water so as to increase reaction velocityand prevent side reactions. For this purpose, in using solvents having ahigh hygroscopic property such as dimethylsulfoxide, sulfolan,dimethylformamide, N-methyl pyrrolidinone and dimethylsulfolan, benzeneor toluene is added therein preferably so as to remove the watertherefrom prior to the substitution reaction.

Halogenated isophthalonitrile and the fluorinating agent are reacted tofully proceed with the fluorination. The reaction temperature is usuallyin the range of 50° C. to 400° C., and preferably in the range of 100°C. to 300° C. The reaction duration is usually 0.5 to 20 hours. Thereaction may be performed under a reduced, normal or a compressedpressure, but preferably either normal or a compressed pressure. In thecase of compressed pressure, it is preferably in the range of 30 to 1000kPa, and more preferably in the range of 100 to 800 kPa.

In the second embodiment, the fluorination may be performed in thepresence of a phase-transfer catalyst so as to heighten the fluorinationreaction velocity. Suitable phase-transfer catalysts include knownphase-transfer catalysts, but for example crown compounds such asdibenzo-18-crown-6-ether and polyethylene glycol: (molecular weight: 300to 600). The catalyst may be added in the range of 0.1 to 10 moles, permole of halogenated isophthalonitrile.

The halogenated trifluoroisophthalonitrile thus obtained can be purifiedby conventional purification methods, for example column chromatographswith silica gel or alumina, distillation preferably solid distillation,re-crystallization, re-precipitation and sublimation.

Step 3b in an embodiment for producing HPC of the present invention willbe explained.

The halogenated trifluoroisophthalic acid can be produced byconventional methods, for example the halogenatedtrifluoroisophthalonitrile thus obtained is hydrolyzed to change thecyano groups to carboxyl groups. Alternatively, the halogenatedtrifluoroisophthalic acid can be also produced by halogenating compoundsin which m-xylene, m-dialkyl benzene and the hydrogen atoms of thesealkyl groups substituted with other atoms or an atomic group, and thenoxidizing the alkyl groups, not depending Step 3a. Among them, thehydrolysis method is preferably cited, so that it will be explainedbelow.

The hydrolysis of halogenated trifluoroisophthalonitrile is performed inthe presence of an acid or base. Suitable acids include concentratedsulfuric acid, trichloroacetic acid, sulfuric acid, polyphosphoric acidsuch as pyrophosphoric acid, triphosphoric acid and tri- andtetra-methaphosphoric acids; trifluoroacetic acid, trifluoroaceticanhydride, hydrochloric acid, fuming sulfuric acid, concentratedhydrochloric acid, hydrobromic acid, propionic acid, formic acid, nitricacid, acetic acid; mixtures thereof for instance trifluoro aceticacid-trifluoroacetic anhydride (mixing ratio by weight: 1:9 to 9:1,preferably 3:7- to 7:3) and trichloroacetic acid-sulfuric acid (mixingratio by weight: 1:9 to 9:1, preferably 3:7 to 7:3). The above acids maybe used singly or in a combination thereof, and as it is or in the formof an aqueous solution. In the case of the solution, the concentrationof acid in aqueous acid solution can be used to fully hydrolyzehalogenated trifluoroisophthalonitrile or more, but for example in therange of 40 to 85% by weight, depending on the reaction temperature andkinds of the acid. Among them, sulfuric acid, in particular an aqueous50 to 80% by weight of sulfuric acid is preferably used. Among them, atleast one selected from the group consisting of polyphosphoric acid,trifluoroacetic acid-trifluoroacetic anhydride, trichloroacetic acid,propionic acid, hydrochloric acid, concentrated hydrochloric acid andsulfuric acid, in particular sulfuric acid, propionic acid, concentratedhydrochloric acid and polyphosphoric acid are preferably used. Suitablebases include sodium hydroxide, lithium hydroxide, potassium hydroxide,rubidium hydroxide, cesium hydroxide, beryllium hydroxide, magnesiumhydroxide, calcium hydroxide, strontium hydroxide and barium hydroxide,and preferably sodium hydroxide, potassium hydroxide, calcium hydroxideand barium hydroxide. Also, the above base may be used singly or in acombination thereof. The acid or base is added to fully hydrolyzehalogenated trifluoroisophthalonitrile, but for example theconcentration of halogenated trifluoroisophthalonitrile to the acid orbase to be added may be in the range of 1 to 80% by weight, andpreferably in the range of 5 to 50% by weight.

Halogenated trifluoroisophthalonitrile should be fully hydrolyzed, butfor instance the hydrolysis temperature is usually in the range of −20°C. to 200° C., preferably in the range of 0° C. to 150° C., and the itsduration is usually in the range of 0.1 to 40 hours, and preferably inthe range of 0.1 to 20 hours. The hydrolysis may be performed under acompressed, normal or a reduced pressure, but preferably normalpressure.

The halogenated trifluoroisophthalic acid thus obtained is purified byconventional purification methods, for example column chromatographswith silica gel or alumina, distillation preferably solid distillation,re-crystallization, re-precipitation and sublimation.

Step 3c in an embodiment for producing the above HPC will be explainedbelow.

In Step 3c, the halogenated trifluoroisophthalic acid thus obtained inStep 3b is reacted with an azide compound in the presence of a Lewisbase in a solvent to form an acid azide wherein the carboxyl groups inhalogenated trifluoroisophthalic acid are changed to —CON₃ groups, andthen this acid azide is thermally rearranged and hydrolyzed, thereby theobjective HPC can be obtained.

Suitable azide compounds include a —N₃ groups, and change the carboxylgroups in halogenated trifluoroisophthalic acid to —CON₃ groups, but forexample include a compound represented by the formula:

wherein R¹ and R² are independently alkyl groups having 1 to 5 carbonatoms, for instance methyl, ethyl, propyl, isopropyl, n-butyl, pentyl,neopentyl, sec-butyl and tert-butyl; cycloalkyl groups having 3 to 8carbon atoms, for instance cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl and cyclooctyl; benzyl; a phenyl group which mayhave a substituted group. Suitable substituents include an alkyl grouphaving 1 to 5 carbon atoms, for example methyl, ethyl, propyl,isopropyl, n-butyl, pentyl, neopentyl, sec-butyl and tert-butyl; analkoxy group having 1 to 5 carbon atoms, for example methoxy, ethoxy,propoxy, isopropoxy, n-butoxy, pentoxy, neopentoxy, sec-butoxy andtert-butoxy; acetyl group, chloroacetyl group, trichloroacetyl group,trifluoroacetyl group, carboxy group, amino group, a halogen atom suchas fluorine, chlorine, bromine or iodine; nitrile group, sulfonyl group,nitro group and an ester group, for example methyl or ethyl ester. Inthis case, R¹ and R² may be identical or not, but for instance includemethyl, ethyl, propyl, tert-butyl, benzyl and phenyl, and particularboth includes phenyl. Diphenylphosphoryl azide (hereinafter it may bereferred to as “DPPA”.) is particularly preferred as the azide compound.

The azide compound may be added so as to effectively proceed with thereaction of halogenated trifluoroisophthalic acid. The amount of theazide compounds is usually in the range of 2 to 50 moles, and preferablyin the range of 2 to 10 moles, per mole of halogenatedtrifluoroisophthalic acid, depending on the kinds or amounts of thehalogenated trifluoroisophthalic acid, Lewis base, and solvent.

In Step 3c, it is essential to react halogenated trifluoroisophthalicacid with an azide compound in the presence of a Lewis base in asolvent. Suitable Lewis bases include an hydroxide of alkali metals suchas sodium hydroxide, lithium hydroxide, potassium hydroxide, rubidiumhydroxide and cesium hydroxide; an hydroxide of alkaline earth metalssuch as beryllium hydroxide, magnesium hydroxide, calcium hydroxide,strontium hydroxide and barium hydroxide; a primary amine such asmethylamine, ethylamine, propylamine and n-, sec- and tert-butylamine,cyclohexylamine, benzylamine and phenylamine; a secondary amine such asdimethylamine, diethylamine, dipropylamine, dibutylamine,di-n-butylamine, di-sec-butylamine, di-tert-butylamine,dicyclohexylamine, dibenzylamine and diphenylamine; a tertiary aminesuch as trimethylamine, triethylamine, tripropylamine, tributylamine,tricyclohexylamine, tribenzylamine and triphenylamine; pyridine; acarbonate of alkali metals or alkaline earth metals such as sodiumhydrogen carbonate, lithium hydrogen carbonate, potassium hydrogencarbonate, rubidium hydrogen carbonate, cesium hydrogen carbonate,sodium carbonate, lithium carbonate, potassium carbonate, rubidiumcarbonate, cesium carbonate, beryllium carbonate, magnesium carbonate,calcium carbonate, strontium carbonate and barium carbonate; a salt ofalkali metals or alkaline earth metals such as potassium fluoride,potassium chloride, sodium fluoride, sodium chloride, calcium chlorideand magnesium chloride, preferably triethylamine, trimethylamine,pyridine, sodium hydrogen carbonate, potassium hydrogen carbonate,potassium fluoride, sodium fluoride, and more preferably triethylamine,trimethylamine and pyridine.

The Lewis base is added to effectively proceed with the reaction ofhalogenated triisophthalonitrile, but for example usually in the rangeof 2 to 50 moles, and preferably in the range of 2 to 10 moles, per moleof halogenated trifluoroisophthalic acid. If the amount is less than 2moles, halogenated trifluoroisophthalic acid does not effectively react,therefore it leads a drop of yields. In contrast, if the amount exceeds50 moles, it does not obtain effects in proportion to additions, leadstime-consuming, and finally increases in costs.

Suitable solvents include alcohols such as methanol, ethanol, dehydratedethanol, isopropanol, benzylalcohol, phenol, and n-, sec- andtert-butanol; halogenated hydrocarbons such as chloroform, methylenechloride, carbon tetrachloride, chloroethane, and di-, tri- andtetra-chloroethane; hydrocarbons such as pentane, hexane, cyclohexaneand heptane; aromatic hydrocarbons such as benzene, toluene and xylene;ethers such as diethylether, isopropylether, tetrahydrofuran (THF),dioxane, diphenylether, benzylether and tert-butylether, preferablyalcohols in view of obtaining urethane which is easily hydrolyzed toamines, and most preferably tert-butanol, benzylalcohol and ethanol inview of obtaining amines easily under mild conditions such as catalyticreduction and acids in a cooled. The solvent may be added so as toeffectively proceed with the reaction of halogenatedtrifluoroisophthalic acid, but for example in such a way that theconcentration of halogenated trifluoroisophthalic acid in the solvent isusually in the range of 1 to 80 (w/v) %, and preferably in the range of5 to 50 (w/v) %.

In Step 3c, halogenated trifluoroisophthalic acid and an azide compoundare reacted to effectively proceed with the reaction, but the reactiontemperature is usually in the range of −20° C. to 200° C., andpreferably in the range of 20° C. to 150° C., and its duration isusually in the range of 0.1 to 40 hours, and preferably in the range of0.1 to 20 hours. The reaction may be performed under a compressed,normal or a reduced pressure, but preferably under a normal pressure inview of easily handling and equipment.

The acid azide thus obtained is thermally rearranged and hydrolyzed, forexample the acid azide is thermally rearranged in a first solvent at atemperature of −20° C. to 200° C., preferably in the range of 20° C. to150° C. for 0.1 to 40 hours, preferably 0.1 to 20 hours, while refluxingif necessary, to form isocyanic ester in which the —CON₃ groups havebeen changed to —NCO groups. This isocyanic ester (10 weight parts) ishydrolyzed in a second solvent at a temperature of −50° C. to 200° C.,preferably in the range of −20° C. to 150° C. for 0.1 to 40 hours,preferably 0.1 to 20 hours, while refluxing if necessary, using an acidor base in the range of 1 to 10000 weight parts, preferably in the rangeof 5 to 1000 weight parts. The objective HPC then can be produced.

Suitable first solvents include esters such as methyl formate, ethylformate, methyl acetate, ethyl acetate and propyl acetate; ketones suchas acetone, MIBK, cyclohexanone and methylethylketone; halogenatedhydrocarbons such as chloroform, methylene chloride, carbontetrachloride, chloroethane and di-, tri- and tetra-chloroethane;hydrocarbons such as pentane, hexane, cyclohexane and heptane; aromatichydrocarbons such as benzene, toluene and xylene; ethers such asdiethylether, isopropylether, THF, dioxane, diphenylether, benzyletherand tert-butylether, and preferably chloroform, benzene and toluene.

Suitable second solvents include alcohols such as methanol, ethanol,dehydrated ethanol, isopropanol, benzylalcohol, phenol and n-, sec-, andtert-butanol; esters such as methyl formate, ethyl formate, methylacetate, ethyl acetate and propyl acetate; ketons such as acetone, MIBK,cyclohexanone and MEK; halogenated hydrocarbons such as chloroform,methylene chloride, carbon tetrachloride, chloroethane and di-, tri-,and tetra-chloroethane; hydrocarbons such as pentane, hexane,cyclohexane and heptane; aromatic hydrocarbons such as benzene, tolueneand xylene; ethers such as diethylether, isopropylether, THF, dioxane,diphenylether, benzylether and tert-butylether, and preferably methanol,ethanol, chloroform, benzene, toluene and ethyl acetate.

Suitable acids to be used in the hydrolysis include concentratedsulfuric acid, trichloroacetic acid, sulfuric acid, pyrophosphoric acid,triphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid,trifluoroacetic acid, trifluoroacetic anhydride, hydrochloric acid,fuming sulfuric acid, concentrated hydrochloric acid, hydrobromic acid,propionic acid, formic acid, nitric acid and acetic acid; and mixturesthereof, for instance trifluoroacetic acid-trifluoroacetic anhydride(weight mixing ratio: 1:9 to 9:1, preferably 3:7 to 7:3) andtrichloroacetic acid-sulfuric acid (weight mixing ratio: 1:9 to 9:1,preferably 3:7 to 7:3). The acid may be used singly or in a combinationthereof. Among them, at least one selected from the group consisting ofconcentrated hydrochloric acid, hydrochloric acid, acetic acid,concentrated sulfuric acid, sulfuric acid, hydrobromic acid, andpropionic acid; in particular concentrated hydrochloric acid,hydrochloric acid or sulfuric acid is preferably used as the acid.Suitable bases to be used in the hydrolysis include sodium hydroxide,lithium hydroxide, potassium hydroxide, rubidium hydroxide, cesiumhydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide,strontium hydroxide and barium hydroxide, and preferably sodiumhydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide.The base may be used singly or in a combination thereof.

In the hydrolysis above, if hydrolysate is present in the form of ahydrochloric acid salt, this hydrolysate may be neutralized with a base.Suitable bases to be used are the same as the above hydrolysis. The acidazide may be used as it is, which is produced from the reaction ofhalogenated trifluoroisophthalic acid and the azide compound. Theconcentration of the acid azide in the first solvent is usually in therange of 1 to 80 (w/v) %, and preferably in the range of 5 to 50 (w/v)%. The isocyanic ester obtained from thermal rearrangement of the acidazide may be used as it is. The concentration of the isocyanic ester inthe second solvent is usually in the range of 1 to 80 (w/v) %, andpreferably in the range of 5 to 50 (w/v)%. Thermal rearrangement andhydrolysis may be performed under a compressed, normal or a reducedpressure, and preferably under normal pressure in view of easy handlingand equipment.

The halogenated trifluoroisophthalic acid obtained in Step 3b is reactedwith an azide compound in the presence of a Lewis base in a solvent toproduce an acid azide in which the carboxyl groups in the halogenatedtrifluoroisophthalic acid are changed to —CON₃ groups. This acid azideis reacted with an alcohol in a steam bath at a temperature of −20° C.to 200° C., preferably 20° C. to 150° C., for 0.1 to 40 hours,preferably 0.1 to 20 hours, while refluxing if necessary, to form aurethane. Further, this urethane is hydrolyzed in a third solvent withan acid or base usually in the range of 1 to 10000 weight parts,preferably in the range of 5 to 1000 weight parts, based on 10 weightparts of the urethane usually at a temperature of −50° C. to 200° C.,preferably of −20° C. to 150° C., for 0.1 to 40 hours, preferably 0.1 to20 hours, while refluxing if necessary. The objective halogenatedm-phenylenediamine then may be produced, instead of Step 3c.

Suitable alcohols to be used in the reaction of the acid azide includemethanol, ethanol, dehydrated ethanol, isopropanol, benzylalcohol,phenol, and n-, sec- and tert-butanol or the like.

The reaction of the acid azide and alcohol may be performed withoutaddition of solvents, since the alcohol is a liquid. However, othersolvents may be added depending on the kinds and amounts of the rawmaterials and reaction conditions. Suitable solvents in this caseinclude water, esters such as methyl formate, ethyl formate, methylacetate, ethyl acetate and propyl acetate; ketones such as acetone,MIBK, cyclohexanone and MEK; halogenated hydrocarbons such aschloroform, methylene chloride, carbon tetrachloride, chloroethane anddi-, tri-, and tetra-chloroethane; hydrocarbons such as pentane, hexane,cyclohexane and heptane; aromatic hydrocarbons such as benzene, tolueneand xylene; ethers such as diethylether, isopropylether, THF, dioxane,diphenylether, benzylether and tert-butylether.

Suitable third solvents to be used in the above hydrolysis includewater; alcohols such as methanol, ethanol, dehydrated ethanol,isopropanol, benzylalcohol, phenol and n-, sec-, and tert-butanol;esters such as methyl formate, ethyl formate, methyl acetate, ethylacetate and propyl acetate; ketons such as acetone, MIBK, cyclohexanoneand MEK; halogenated hydrocarbons such as chloroform, methylenechloride, carbon tetrachloride, carbon tetrachloride, chloroethane anddi-, tri-, and tetra-chloroethane; hydrocarbons such as pentane, hexane,cyclohexane and heptane; aromatic hydrocarbons such as benzene, tolueneand xylene; ethers such as diethylether, isopropylether, THF, dioxane,diphenylether, benzylether and tert-butylether, and preferably methanol,ethanol, chloroform, benzene, toluene and ethyl acetate.

Suitable acids to be used in the hydrolysis include concentratedsulfuric acid, trichloroacetic acid, sulfuric acid, pyrophosphoric acid,triphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid,trifluoroacetic acid, trifluoroacetic anhydride, hydrochloric acid,fuming sulfuric acid, concentrated hydrochloric acid, hydrobromic acid,propionic acid, formic acid, nitric acid and acetic acid; and mixturesthereof, for instance trifluoroacetic acid-trifluoroacetic anhydride(weight mixing ratio: 1:9 to 9:1, preferably 3:7 to 7:3) andtrichloroacetic acid-sulfuric acid (weight mixing ratio: 1:9 to 9:1,preferably 3:7 to 7:3). The acid may be used singly or in a combinationthereof. Among them, at least one selected from the group consisting ofconcentrated hydrochloric acid, hydrochloric acid, acetic acid,concentrated sulfuric acid, sulfuric acid, hydrobromic acid, andpropionic acid; in particular concentrated hydrochloric acid,hydrochloric acid or sulfuric acid is preferably used as the acid.Suitable bases to be used in the hydrolysis include sodium hydroxide,lithium hydroxide, potassium hydroxide, rubidium hydroxide, cesiumhydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide,strontium hydroxide and barium hydroxide, and preferably sodiumhydroxide, potassium hydroxide, lithium hydroxide and calcium hydroxide.The base may be used singly or in a combination thereof.

In the hydrolysis above, if hydrolysate is present in the form of ahydrochloric acid salt, this hydrolysate may be neutralized with a base.Suitable bases to be used are the same as the above hydrolysis. The acidazide may be used as it is, as described above. The concentration of theacid azide in the alcohol and other solvent added is usually in therange of 1 to 80 (w/v) %, and preferably in the range of 5 to 50 (w/v)%. The urethane obtained from thermal rearrangement of the acid azidemay be used as it is. The concentration of the urethane in the thirdsolvent is usually in the range of 1 to 80 (w/v) %, and preferably inthe range of 5 to 50 (w/v) %. Thermal rearrangement and hydrolysis maybe performed under a compressed, normal or a reduced pressure, andpreferably under normal pressure in view of easy handling and equipment.

The TPC thus obtained can be purified by conventional purifications, forexample column chromatographs with silica gel or alumina, distillationpreferably solid distillation, re-crystallization, re-precipitation andsublimation.

The tetrafluoro-m-phenylenediamine including HPC are importantintermediates for synthesizing dye, medicine, agricultural chemical andmacromolecule compounds, and useful for raw materials of resinsexcellent in heat resistance, water repellent property, chemicalresistance, and low dielectric property. Furthermore, these are suitablyused for charge-transfer agents (in particular positive hole-transferagents) in the fields of solar battery, electroluminescent elements, andelectrophotography photosensitive body.

The HPC has a relatively high melting point, and low solubility intodimethylacetoamide, thus excels in heat resistance and chemicalresistance.

In accordance with the present invention, it can provide new HPC. TheHPCs are important intermediates for synthesizing dye, medicine,agricultural chemical and macromolecule compounds, and expected to beuseful for raw materials of resins excellent in heat resistance, waterrepellent property, chemical resistance, and low dielectric property.

(Fluorine Compound)

The present invention relates to a fluorine compound represented by theformula 41:

In Formula 41, n indicates the bonding number of bromine atom to thebenzene ring, an integer of 1 to 3, preferably 1 or 2, and morepreferably 1. The bonding place of the bromine atom to the benzene ringdepends on the bonding number of the bromine atom and the property ofthe objective fluorine compound. For example, one bromine atom bonds tothe position 4 or 5 of the benzene ring if n is 1, and two bromine atomsbond to the positions 4 and 6 thereof if n is 2.

In formula 41, Y¹ and Y² indicate carboxyl (—COOH) or cyano (—CN)groups, wherein Y¹ and Y² may be same or not, but preferably same. Theterm m indicates the bonding number of fluorine atom to the benzenering, an integer of 3 to 1, preferably 3 or 2, and more preferably 3. Inthe formula 41, the sum of n and m is 4, so that the compoundrepresented by the formula 41 does not have any carbon-hydrogen bonds.

Suitable fluorine compounds of the present invention include4-bromo-2,5,6-trifluoroisophthalonitrile,5-bromo-2,4,6-trifluoroisophthalonitrile,4,6-dibromo-2,5-difluoroisophthalonitrile,4-bromo-2,5,6-trifluoroisophthalonitrile,5-bromo-2,4,6-trifluoroisophthalonitrile, and4,6-dibromo-2,5-difluoroisophthalonitrile.

In the above compounds, trifluoroisophthalonitrile compounds andtrifluoroisophthalic acids are referred to as halogenatedtrifluoroisophthalonitrile and halogenated trifluoroisophthalic acid,respectively.

Among them, 4-bromo-2,5,6-trifluoroisophthalonitrile and4-bromo-2,5,6-trifluoroisophthalic acid are preferable.

The fluorine compound of the present invention may be produced byconventional methods. The present method can be divided into two:halogenated trifluoroisophthalonitrile and halogenated trifluorophthalicacid.

The methods of halogenated trifluoroisophthalonitrile of the presentinvention will be explained. The halogenated trifluoroisophthalonitrilewill be produced by the conventional methods, for example the methoddescribed in JP-B-63-5023.

A first embodiment for producing a halogenatedtrifluoroisophthalonitrile of the present invention will be explainedbelow. Tetrafluoroisophthalonitrile is reacted with a brominating agentto replace the fluorine atom bonded to the benzene ring with the bromineatom. For example, by specifically substituting the fluorine at the4-position in tetrafluoroisophthalonitrile,4-bromo-2,5,6-trifluoroisophthalonitrile can be obtained in a highyield.

Suitable brominating agents include known brominating agents, but forexample sodium bromide, potassium bromide and lithium bromide. Sodiumbromide and potassium bromide are preferable in view of readily handlingand availability.

The brominating agent may be added to specifically substitute thefluorine atom at the 4-position in tetrafluoroisophthalonitrile with abromine atom or more, but for example in the range of 1 to 5 moles, andpreferably in the range of 1 to 2 moles, per mol oftetrafluoroisophthalonitrile. If it exceeds 5 moles, there is a fearthat fluorine atoms except for the 4-position intetrafluoroisophthalonitrile will be substituted with a bromine atom,and further it is necessary to treat the remaining brominating agent,and therefore not economically. In contrast, if it is less than 1 mole,the fluorine atom in the 4-position will not be fully substituted withsuch an agent, and unreacted raw material will remain in a large amount.

The bromination of tetrafluoroisophthalonitrile may be performed in thepresence or absence of a solvent, but preferably in the presence of thesolvent. Suitable solvents include those which do not block such abromination, and are inert for the brominating agent, but for examplenitrites such as acetonitrile and benzonitrile; ketones such as acetone,methylisobutylketone (MIBK), methylethylketone (MEK) and cyclohexanone;halogenated hydrocarbons such as chloroform, methylene chloride, carbontetrachloride, chloroethane and di-, tri-, tetra-chloroethane; aromatichydrocarbons such as benzene, toluene and xylene; hydrocarbons such aspentane, hexane, cyclohexane and heptane; ethers such as diethylether,isopropylether, tetrahydrofuran (THF), dioxane, diphenylether,benzylether and tert-butylether; esters such as methyl formate, ethylformate, methyl acetate, ethyl acetate, propyl acetate and isopropylacetate; N-methylpyrrolidinone (NMP), dimethylformamide (DMF),dimethylsulfoxide (DMSO), dimethylacetamide, sulfolan (TMSO₂) anddimethylsulfolan (DMSO₂); and more preferably acetonitrile,benzonitrile, NMP, DMF and DMSO. The solvent may be used in such a waythat the concentration of tetrafluoroisophthalonitrile in the solvent isusually in the range of 2 to 80 (w/v) %, and more preferably in therange of 5 to 50 (w/v) %. The bromination reaction may be performedpreferably free from water so as to improve reaction velocity andprevent side reactions. In using solvents having a high hygroscopicproperty such as dimethylsulfoxide, sulfolan, dimethylformamide,N-methylpyrrolidinone and dimethylsulforan, benzene or toluene is addedtherein preferably so as to remove the water therefrom prior to thesubstitution reaction.

Tetrafluoroisophthalonitrile and the brominating agent are reacted tofully proceed with the halogen substitution reaction, but the reactiontemperature is usually in the range of 0° C. to 300° C., and preferablyin the range of 50° C. to 250° C., and the reaction duration is usuallyin the range of 0.5 to 20 hours. The reaction may be performed under areduced, normal or a compressed pressure, and preferably at normalpressure.

In a second embodiment, a halogenated trifluoroisophthalonitrile may beproduced by fluorinating tetrabromoisophthalonitrile with a fluorinatingagent. The bromine atoms in the 2, 4, and 6 positions intetrabromoisophthalonitrile are specifically substituted with thefluorine atoms by means of nucleophilic substitution reaction to form adesired 5-bromo-2,4,6-trifluoroisophthalonitrile in a high yield.

Suitable fluorinating agents include known fluorinating agents, but forexample potassium fluoride, cesium fluoride, sodium fluoride, bariumfluoride, calcium fluoride and antimony fluoride, and preferablypotassium fluoride in view of handling property and acquisition withease.

The fluorinating agent may be added to specifically fluorinate thebromine atoms in the 2,4,6 positions in tetrabromoisophthalonitrile, butstoichiometrically three times per mole of the raw material. Concretely,the fluorinating agent is usually in the range of 3 to 20 moles, andpreferably 3 to 10 moles, per mole of tetrabromoisophthalonitrile. If itexceeds 20 moles, there is a fear that the 5-position will beadditionally fluorinated, and further it is necessary to treat theremaining fluorinating agents, so that not economical. In contrast, ifit is less than 3 moles, the bromine atoms in the 2, 4, 6 positions arenot fully fluorinated, thereby the yield of the objective product willbe lowered.

The fluorinating reaction for tetrabromoisophthalonitrile may beperformed in the presence or absence of a solvent, but preferably in thepresence of the solvent. Suitable solvents include those which do notblock the fluorinating reaction and are inert fortetrabromoisophthalonitrile and the fluorinating agents, but for examplebenzonitrile, DMSO, sulfolan (TMSO₂), DMF, N-methylpyrrolidinone (NMP),dimethylsulfolan (DMSO₂), acetonitrile, acetone, MEK and MIBK, andpreferably benzonitrile and acetonitrile. The solvent may be used insuch a way that the concentration of tetrabromoisophthalonitrile isusually in the range of 1 to 80 (w/v) %, and preferably 5 to 50 (w/v) %.The fluorination is preferably performed free from water so as toincrease reaction velocity and prevent side reactions. For this purpose,in using solvents having a high hygroscopic property such asdimethylsulfoxide, sulfolan, dimethylformamide, N-methylpyrrolidinoneand dimethylsulforan, benzene or toluene is added therein preferably soas to remove the water therefrom prior to the substitution reaction.

Tetrabromoisophthalonitrile and the fluorinating agent are reacted tofully proceed with the fluorination. The reaction temperature is usuallyin the range of 50° C. to 400° C., and preferably in the range of 100°C. to 300° C. The reaction duration is usually 0.5 to 20 hours. Thereaction may be performed under a reduced, normal or a compressedpressure, but preferably either normal or a compressed pressure. In thecase of a compressed pressure, it is preferably in the range of 30 to1000 kPa, and more preferably in the range of 100 to 800 kPa.

The fluorination may be performed in the presence of a phase-transfercatalyst so as to heighten the fluorination reaction velocity. Suitablephase-transfer catalysts include known phase-transfer catalysts, but forexample crown compounds such as dibenzo-18-crown-6-ether andpolyethylene glycol (molecular weight: 300 to 600). The catalyst may beadded in the range of 0.1 to 10 moles, per mole oftetrabromoisophthalonitrile.

The halogenated trifluoroisophthalonitrile thus obtained can be purifiedby conventional purifications, for example column chromatographs withsilica gel or alumina, distillation preferably solid distillation,re-crystallization, re-precipitation and sublimation.

The method of halogenated trifluoroisophthalic acid of the presentinvention will be explained.

The halogenated trifluoroisophthalic acid of the present invention canbe produced by conventional methods, for example the halogenatedtrifluoroisophthalonitrile thus obtained is hydrolyzed to change thecyano groups to carboxyl groups. Alternatively, the halogenatedtrifluoroisophthalic acid can be also produced by halogenating compoundsin which m-xylene, m-dialkyl benzene and the hydrogen atoms of thesealkyl groups substituted with other atoms or an atomic group, and thenoxidizing the alkyl groups. Among them, the hydrolysis method ispreferably cited, so that it will be explained below.

The hydrolysis of halogenated trifluoroisophthalonitrile is performed inthe presence of an acid or base. Suitable acids include concentratedsulfuric acid, trichloroacetic acid, sulfuric acid, pyrophosphoric acid,triphosphoric acid and tri- and tetra-metaphosphoric acid;trifluoroacetic acid, trifluoroacetic anhydride, hydrochloric acid,fuming sulfuric acid, concentrated hydrochloric acid, hydrobromic acid,propionic acid, formic acid, nitric acid, acetic acid; mixtures thereoffor instance trifluoro acetic acid-trifluoroacetic anhydride (mixingratio by weight: 1:9 to 9:1, preferably 3:7 to 7:3) and trichloroaceticacid-sulfuric acid (mixing ratio by weight: 1:9 to 9:1, preferably 3:7to 7:3). The above acid may be used singly or in a combination thereof,and as it is or in the form of an aqueous solution. In the case of thesolution, the acid can be used to fully hydrolyze halogenatedtrifluoroisophthalonitrile or more, but for example in the range of 40to 85% by weight, depending on the reaction temperature and kinds of theacid. Among them, sulfuric acid, in particular an aqueous 50 to 80% byweight of sulfuric acid is preferably used. Among them, at least oneselected from the group consisting of polyphosphoric acid,trifluoroacetic acid-trifluoroacetic anhydride, trichloroacetic acid,propionic acid, hydrochloric acid, concentrated hydrochloric acid andsulfuric acid, in particular sulfuric acid, propionic acid, concentratedhydrochloric acid and polyphosphoric acid are preferably used. Suitablebases include sodium hydroxide, lithium hydroxide, potassium hydroxiderubidium hydroxide, cesium hydroxide, beryllium hydroxide, magnesiumhydroxide, calcium hydroxide, strontium hydroxide and barium hydroxide,and preferably sodium hydroxide, potassium hydroxide, calcium hydroxideand barium hydroxide. Also, the above base may be used singly or in acombination thereof. The acid or base is added to fully hydrolyzehalogenated trifluoroisophthalonitrile, but for example theconcentration of halogenated trifluoroisophthalonitrile to the acid orbase to be added may be in the range of 1 to 80% by weight, andpreferably in the range of 5 to 50% by weight.

Halogenated trifluoroisophthalonitriles should be fully hydrolyzed, butfor instance the hydrolysis temperature is usually in the range of −20°C. to 200° C., preferably in the range of 0° C. to 150° C., and itsduration is usually in the range of 0.1 to 40 hours, and preferably inthe range of 0.1 to 20 hours. The hydrolysis may be performed under acompressed, normal or a reduced pressure, and preferably under a normalpressure.

The halogenated trifluoroisophthalic acid thus obtained is purified byconventional purifications, for example column chromatographs withsilica gel or alumina, distillation preferably solid distillation,re-crystallization, re-precipitation and sublimation.

The tetrafluoro-m-phenylenediamine including HPC are importantintermediates for synthesizing dye, medicine, agricultural chemical andmacromolecule compounds, and useful for raw materials of resinsexcellent in heat resistance, water repellent property, chemicalresistance, and low dielectric property. Furthermore, these are suitablyused for charge-transfer agents (in particular positive hole-transferagents) in the fields of solar battery, electroluminescent elements, andelectrophotography photosensitive body.

In accordance with the present invention, it can provide new fluorinecompounds. The fluorine compounds are important intermediates forsynthesizing dye, medicine, agricultural chemical and macromoleculecompounds, and expected to be useful for raw materials of resinsexcellent in heat resistance, water repellent property, chemicalresistance, and low dielectric property.

EXAMPLE

Now, the present invention will be explained referring to examples, butnot restricted by these examples.

(HAA)

Synthesis Example 1

In a 500 ml 4-necked flask, were poured 71.15 g (355 mmol) oftetrafluorophthalonitrile, 2.16 g (37.1 mmol) of potassium fluoride and210 g of acetonitrile, and resulting was heated to 80° C. This mixturewas kept at 80° C. with stirring, and to this mixture were dropped 4.40g (17.7 mmol) of tetrachlorohydroquinone in 200 ml of acetonitrile over1 hour. After dropping, reaction was performed at 80° C. for 6 hours.The reaction solution was cooled, filtrated, and the resulting residuewashed with 30 ml and 15 ml of acetonitrile. After the filtrate had beenconcentrated on an evaporator to remove the solvent, 62.34 g oftetrafluorophthalonitrile was removed under in vacuo. To this was poured27 ml of toluene and reflux performed for 1 hour. After cooling, theresidue was washed with 5 ml, 25 ml and 5 ml of toluene, respectively,and further 12 ml of deionized water for three times. Finally, by dryingthe residue at 70° C. in vacuo, 9.08 g of1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene were obtained(yield: 84%).

Synthesis Example 2

In a 100 ml 3-necked flask, were poured 69.2 g of a 70% sulfuric acidand 4.2 g of 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzenesynthesized in Synthesis Example 1. The inner temperature was heated to130° C., and continued for 6 hours at this temperature. Then, to thereaction solution were added 175 g of ice water to precipitate. Afterfiltration, the residue was washed with 30 ml of water for 2 times.Then, this residue was re-crystallized in 400 ml of an aqueous 10 wt. %acetone solution.

After repeating the procedure as the above for 4 times, vacuum drying at100° C. for 16 hours were performed to give 8.63 g of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (yield: 71%).

Example 1

In a 100 ml 3-necked flask, were added 3.45 g (5.04 mmol) of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene synthesized inSynthesis Example 2 and 53.5 g (640.72 mmol) of thionyl chloride, andthe inner temperature was heated to 70° C. After reaction at thistemperature for 3 hours, the reaction solution was cooled. Then, 9.4 gof thionyl chloride were removed from the solution with a Dean-Starktube, and then 8 ml of acetone were added and mixed. After filtration,the crystal was washed in 10 ml of toluene with stirring. Afterfiltration, the residue was washed with toluene. The resulting crystalwas dried in vacuo (100° C. for 20 hours) to offer 8.4 g of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride(yield: 72.9%).

This product was measured by a mass spectrum analysis to be foundM⁺=646. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 1 was obtained. Melting Point(ThermoGravimetry-Differential Thermal Analysis available from SeikoInstruments in Japan): 305° C. The solubility to dimethylacetoamide at25° C. was 22 wt. %. This solution was left standing for a night, butprecipitations were not found.

(HTC)

Example II-1 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene

In a 500 ml 4-necked flask, were placed 71.15 g (355 mmol) oftatrafluorophthalonitrile, 2.16 g (37.1 mmol) of potassium fluoride and210 g of acetonitrile, and the inner temperature was heated to 80° C.While this mixture was stirred at 80° C., 4.40 g (17.7 mmol) oftetrachlorohydroquinone in 200 ml of acetonitrile were dropped over 1hour. After dropping, reaction was performed at 80° C. for 6 hours, thereaction solution cooled. After filtration, the residue was washed with30 ml and 15 ml of acetonitrile, respectively. After the filtrate hadbeen concentrated on an evaporator to remove the solvent, 62.34 g oftetrafluorophthalonitrile was removed under in vacuo. To this was poured27 ml of toluene and reflux performed for 1 hour. After cooling, theresidue was washed with 5 ml, 25 ml and 5 ml of toluene, respectively,and further 12 ml of deionized water for three times. Finally, by dryingthe residue at 70° C. in vacuo, 9.08 g of1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene were obtained(yield: 84% based on tetrachlorohydroquinone).

This product was measured by a mass spectrum analysis to be foundM⁺=606. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 2 was obtained.

Example II-2 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene

In a 100 ml 3-necked flask, were poured 69.2 g of a 70% sulfuric acidand 4.2 g of 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzenesynthesized in Example II-1. The inner temperature was heated to 130°C., and continued for 6 hours at this temperature. Then, to the reactionsolution were added 175 g of ice water to precipitate. After filtration,the residue was washed with 30 ml of water for 2 times. Then, thisresidue was re-crystallized in 400 ml of an aqueous 10 wt. % acetonesolution.

After repeating the procedure as the above for 4 times, vacuum drying at100° C. for 16 hours was performed to give 8.63 g of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (yield: 71%based on 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene).

This product was measured by a mass spectrum analysis to be foundM⁺=682. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 3 was obtained.

Example II-3

In a 1000 ml 4-necked flask, were placed 50 g of1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene synthesized inExample II-1 and 350 ml of propionic acid. While stirring this mixtureat 130° C., 150 ml of a 70 wt. % sulfuric acid were dropped over 1 hour,and then refluxed for 6 hours. After cooling, the refluxed solution waspoured into 1.5 liter of ice water. After filtration, the residue waswashed with 100 ml of water, and then re-crystallized in 500 ml of anaqueous 10 wt. % acetone solution. The re-crystallization procedure wasrepeated once. The resulting crystal was dried at 100° C. for 5 hours togive 43.9 g of 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene(yield: 78% based on1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene).

Example II-4

In a 3000 ml 4-necked flask, were placed 0.50 g of1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene synthesized inExample II-1 and 700 ml of acetic acid. While stirring this mixture at100° C., 300 ml of a 70 wt. % sulfuric acid were dropped over 1 hour,and then refluxed for 14 hours. After cooling, the refluxed solution waspoured into 1.5 liter of ice water. After filtration, the residue waswashed with 100 ml of water, and then re-crystallized in 400 ml of anaqueous 10 wt. % acetone solution twice. The resulting crystal was driedat 100° C. for 5 hours to give 38.2 g of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene (yield: 68%based on 1,4-bis(3,4-dicyanotrifluorophenoxy)tetrachlorobenzene).

Example II-5 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzenedianhydride

In a 100 ml 3-necked flask, were added 3.45 g (5.04 mmol) of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene synthesized inExample II-2 and 53.5 g (640.72 mmol) of thionyl chloride, and the innertemperature was heated to 70° C. After reaction at this temperature for3 hours, the reaction solution was cooled. Then, 9.4 g of thionylchloride were removed from the solution with a Dean-Stark tube, and then8 ml of acetone were added and mixed. After filtration, the crystal waswashed in 10 ml of toluene with stirring. After filtration, the residuewas washed with 15 ml of toluene. The resulting crystal was dried invacuo (100° C. for 20 hours) to offer 8.4 g of1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene dianhydride(yield: 72.9%: based on1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzene).

(HPC)

Synthesis Example III-1

In a 3 liter reaction vessel, were added 200 g (1.00 mol) oftetrafluoroisophthalonitrile, 1 liter of N-dimethylformamide (DMF) and102.7 g (1.00 mol) of sodium bromide (NaBr). This mixture was heated at120° C. for 1 hour. Separately, 3 liter of water was poured to a 5 literof beaker, and to which was poured the resulting reaction solution.After suction filtration, the residue was washed with water and hexane,and then dried in vacuo to offer 198.2 g of a white solid. The solid waspurified by means of solid distillation to give 142.8 g (0.55 mol) of4-bromo-2,5,6-trifluoroisophthalonitrile as a white solid (yield: 55%).

This product was measured by a mass spectrum analysis to be foundM⁺=260. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 4 was obtained.

Synthesis Example III-2

In a 500 ml autoclave made of stainless steel, were placed 200.0 g ofbenzonitrile, 80.0 g (0.301 mol) of tetrachloroisophthalonitrile and83.9 g (1.445 mol) of finely divided, dried potassium fluoride, and theair therein was replaced with nitrogen gas. This mixture was heated at220° C. for 18 hours with stirring. The reactant was cooled to roomtemperature, and suspended potassium chloride and unreacted potassiumfluoride were removed by means of filtration. By removing benzonitrilefrom the filtrate by vacuum distillation, 42.8 g (0.198 mole) of5-chloro-2,4,6-trifluoroisophthalonitrile were obtained as a white solid(yield: 65.8%).

Synthesis Example III-3

In a 5 liter reaction vessel, 250 g (1.15 mol) of5-chloro-2,4,6-trifluoroisophthalonitrile and 2500 ml of an aqueous 62%sulfuric acid solution, and then reflux was performed for 3 hours. Thissolution was cooled to 25° C. After filtration, the crystal wasdissolved in 500 ml of isopropyl ether (IPE), and then washed with 500ml of a saturated aqueous NaCl solution. Then, this crystal was driedwith magnesium sulfate, and by removing the solvent (IPE) by anevaporator, 280.3 g (1.10 mol) of 5-chloro-2,4,6-trifluoroisophthalicacid were obtained as a white solid (yield: 95.4%).

Synthesis Example III-4

In a 200 ml 4-necked flask, were added 20.03 g (76.74 mmol) of4-bromo-2,5,6-trifluoroisophthalonitrile, 40 ml of an aqueous 62%sulfuric acid solution and 40 ml of propionic acid, and reflux wasperformed at 130° C. for 18 hours. This solution was cooled to roomtemperature. After suction filtration, the residue was washed with asmall amount of water. Then, this crystal was dissolved into 200 ml ofIPE, and washed with 100 ml of water and 100 ml of a saturated aqueousNaCl solution. Further, this crystal was dried with magnesium sulfate,and the IPE removed on an evaporator to give 17.2 g (57.53 mmol) of awhite solid of 4-bromo-2,5,6-trifluoroisophthalic acid (yield: 75.0%).

This product was measured by a mass spectrum analysis to be foundM⁺=298. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 5 was obtained.

Example III-1

In a 5 liter reaction vessel, were placed 280.3 g (1.10 mol) of5-chloro-2,4,6-trifluoroisophthalic acid obtained in Synthesis ExampleIII-3, 815.1 g of tert-butanol and 266.7 g (2.64 mol) of triethylamine,and this mixture was heated to 80° C. with stirring. To the mixture,were dropped 726.9 g (2.64 mol) of diphenylphosphoryl azide over 2 hourswith stirring. After dropping, the mixture was heated at 100° C. foradditional 1 hour, and then cooled to 25° C. The solvent of tert-butanolwas removed on an evaporator to give a brownish viscous liquid.

Then, in a separate 5 liter reaction vessel, were added the viscousliquid thus obtained and 915 ml of ethyl acetate, while stirring at roomtemperature 1200 ml of concentrated hydrochloric acid were dropped andadditional stirring was continued for 18 hours. This reaction solutionwas diluted with 1500 ml of water, and then washed with chloroform. Thewashed reaction solution was neutralized with 5N aqueous NaOH solution,and then cooled to 25° C. to form a precipitate. After suctionfiltration, the residue was dissolved into 500 ml of toluene, washedwith a saturated aqueous NaCl solution, and then dried with magnesiumsulfate. After removal of the solvent (ethyl acetate) on an evaporator,the solid obtained was dried in vacuo at room temperature for 3 hours.After distillation of the solid obtained, by re-crystallization with atoluene-hexane mixed solution (volume ratio: 2:3), 117.6 g (0.60 mol) ofa white solid of 5-chloro-2,4,6-trifluoro-m-phenylenediamine wasproduced (yield: 54.2%).

This product was measured by a mass spectrum analysis to be foundM⁺=196. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 6 was obtained. Melting Point (FP800Thermosystem available from Mettler in Germany): 132° C. The solubilityto dimethylacetoamide at 25° C. was 68 wt. %. This solution was leftstanding for a night, but precipitations were not found.

Example III-2

In a one liter reaction vessel, were placed 16.9 g (56.52 mmol) of4-bromo-2,5,6-trifluoroisophthalic acid obtained in Synthesis ExampleIII-4, 260.8 g of tert-butanol, 11.6 g (114.64 mmol) of triethylamineand 31.4 g (114.04 mmol) of diphenylphosphoryl azide, and then thismixture was heated at 100° C. for 17 hours. This reaction solution wasconcentrated on an evaporator to remove the solvent, and then dissolvedin 350 ml of chloroform. Then, this solution was washed with 150 ml of asaturated NaHCO₃ solution, 150 ml of 1% HCl and 150 ml of water twice,respectively, and then dried with magnesium sulfate. By removing thesolvent on the evaporator, a brownish viscous liquid was obtained.

Then, in a 300 ml reaction vessel, were added the viscous liquid thusobtained, 140 ml of ethyl acetate and 23 ml of concentrated hydrochloricacid, and the mixture was stirred at 40° C. for 3 hours. After stirring,this reaction solution and 250 ml of water were added in a 500 ml ofbeaker, stirred for 30 minutes. After standing, 2-layers occurred. Theseparated oil layer (approximately 130 ml) and 200 ml of 5N aqueous NaOHsolution were added in a 500 ml beaker, and then stirred for 15 minutesto form a white precipitate. This white precipitate was suctionfiltrated, and then washed with water to give 9.35 g of a slightbrownish solid. This solid was re-crystallized in a toluene-hexane (1:1by volume) mixed solution to give 7.14 g (29.62 mmol) of a white solidof 4-bromo-2,5,6-trifluoro-m-phenylenediamine (yield: 52.1%).

This product was measured by a mass spectrum analysis to be foundM⁺=240. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 7 was obtained.

(Fluorine Compound)

Example IV-1

In a 3 liter reaction vessel, were added 200 g (1.00 mol) oftetrafluoroisophthalonitrile, 1 liter of N-dimethylformamide (DMF) and102.7 g (1.00 mol) of NaBr. This mixture was heated at 120° C. for 1hour. 3 Liter of water were added in a 5 liter beaker, and then thereaction solution thus obtained was added. After suction filtration, theresidue was washed with water and hexane, and dried in vacuo to give198.2 g of a white solid. After solid distillation, 142.8 g (0.55 mol)of a white solid of 4-bromo-2,5,6-trifluoroisophthalonitrile wereobtained (yield: 55%).

This product was measured by a mass spectrum analysis to be foundM⁺=260. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 8 was obtained.

Example IV-2

In a 200 ml 4-necked flask, were added 20.03 g (76.74 mmol) of4-bromo-2,5,6-trifluoroisophthalonitrile, 40 ml of an aqueous 62%sulfuric acid solution and 40 ml of propionic acid, the mixture wasrefluxed at 130° C. for 18 hours. This solution was cooled to roomtemperature to precipitate a crystal. After suction filtration, thecrystal was washed with a small amount of water. Then, the crystal wasdissolved in 200 ml of IPE, and then washed with 100 ml of water and 100ml of a saturated aqueous NaCl solution. Further, the crystal was driedwith magnesium sulfate, and the IPE was removed on an evaporator to give17.2 g (57.53 mmol) of a white solid of4-bromo-2,5,6-trifluoroisophthalic acid (yield: 75.0%).

This product was measured by a mass spectrum analysis to be foundM⁺=298. When the product was analyzed by a ¹⁹F-NMR spectrometer, thespectrum depicted in FIG. 9 was obtained.

The entire disclosure of Japanese Patent Application Nos. 2001-142028,2001-142029, 2001-142031 and 2001-142032 filed on May 11, 2001,respectively, including specifications, claims, drawings and summary areincorporated herein by reference in its entirety.

1. A halogen-containing aromatic acid dianhydride represented by theformula 1:

wherein X is a chlorine, bromine or iodine atom, m is an integer of 1 to4, n is an integer of 3 to 0, and the sum of n and m is
 4. 2. Adianhydride according to claim 1, wherein X is a chlorine atom, m is 4,and n is
 0. 3. A dianhydride according to claim 1, wherein thedianhydride is 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzenedianhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrabromobenzenedianhydride,1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-chlorotrifluorobenzenedianhydride or1,4-bis(3,4-dicarboxytrifluorophenoxy)-2-bromotrifluorobenzenedianhydride.
 4. A dianhydride according to claim 1, wherein thedianhydride is 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrachlorobenzenedianhydride.